Buccal mucosal |
When you first look at this slide you may think that it looks like a bunch of dirt. The slide was made by scraping some of the surface cells from the lining (buccal mucosa) of someones cheek. Then the cells were smeared onto a clean slide and stained--thats why this kind of preparation is called a smear. Because of the way the tissue is prepared, it doesnt look like the intact tissue in the mouth. Many of the cells have separated and some of them are piled up on top of each other. Thats why you see some dark blobs on the slide--so many cells are piled up that very little light can get through. Some of these are marked with arrows on the image so that you can learn to avoid them at higher magnifications. You should be looking at an area of the slide where cells are not overlapping each other. Some people dont use the 4X (scanning) objective when looking at slides because they cant see individual cells at that magnification. But they are missing the point. When studying tissues, the scanning objective is used to find the best place to look at under a higher magnification. When studying organs, there are some structures that are too large to be seen using the 10X of 40X objectives, and you have to use the 4X objective just to find them. |
Buccal mucosal |
Now you can see individual simple squamous epithelial cells (sse). The most obvious thing in each cell is its nucleus which is round and stained fairly darkly. Its diameter is small compared to the total diameter of the cell. The cytoplasm is difficult to see because it is very thin and doesnt stain darkly. One of the problems with this type of tissue preparation is that the cells lose most of their connections to each other. Compare this image to the drawing of simple squamous epithelium in your textbook, which shows what an intact layer of cells should look like. |
Buccal mucosal |
In the center of this image are two simple squamous epithelial cells that are still attached to each other. Notice that the location of the nucleus (nuc) is in the center of the cell. It is surrounded by the much paler cytoplasm (cyt). |